A close pass by one of the larger bull sharks in Playa Del Carmen (Click to enlarge)

A close pass by one of the larger bull sharks in Playa Del Carmen (Click to enlarge)

I flew 3,000 miles, dove 70 feet underwater, and was now face-to-face with nearly a dozen 500 pound bull sharks, known to be among of the oceans most deadly predators. After three days of diving with them, my perceptions of these beautiful animals changed, and I was left with one of my most rewarding dive trips ever.

• • •

Words & Photos by Chris Constantine

In January, I joined a mission with the Undersea Voyager Project to dive in Playa Del Carmen, a town of about 150,000, located 45 minutes from Cancun on the Yucatan Peninsula. The five-day trip included three days of diving with Dive Balam – a dive center operating out of the Royal Haciendas Resort – operated by one of the region’s most experienced shark diving experts, Marcos Mier. Our mission was threefold; to observe bull sharks feeding in their natural environment, to help Dive Balam and the Undersea Voyager Project educate others and protect the bull sharks and safeguard the opportunities they provide to divers and tourism, and to conduct research to see if bull sharks might be able to help reduce the invasive lion fish populations which are wreaking havoc in the Caribbean. To our benefit, our trip also took place at a time of year when the conditions in Playa Del Carmen are nearly perfect for diving.

Included in our team was filmmaker Steffan Schulz of Strange Media and two filmmakers from Tuna Cinema in Mexico who were filming a story on Marcos, Scott Cassell (of the Undersea Voyager Project), and the bull sharks. Dylen Atkinson and Undersea Voyager Project members Gregg Mikolasek, Sid, Tom, and Carry Loomis also joined the crew and brought back great photos and video footage of the expedition.  Luminox Mexico sponsored all of the dive operations for the team and supported the research being done by the Undersea Voyager Project and Dive Balam.

Luis Lombardo and Mauricio Hoyos, Ph.D. (affectionately called Dr. Shark), from Saving Our Sharks (SOS) were also instrumental in the mission and for ongoing efforts to protect the bull sharks of Playa Del Carmen. The SOS team literally wrote the best practices manual for bull shark diving and has created an ID guide of most of the sharks that have been visiting Playa since 2013. It with Luis and Mauricio’s help that Scott and the Undersea Voyager Project team was able to dive safely with the sharks and help further local conservation efforts.

Dive Balam at the Royal Haciendas resort

Dive Balam at the Royal Haciendas resort

Dive Balam

At the Royal Haciendas Resort (about 10 minutes from Playa Del Carmen), Marcos Mier and the team at Dive Balam operate a dive center with full rental gear, all levels of instruction (PADI, TDI, NACD, from Open Water Diver through to dive master training and specialties), and lead trips to all the local dive destinations. On any given day, they’ll be teaching a brand new diver how to clear their mask while taking another diver cave or cenote diving, guiding a trip to nearby Cozumel, and leading a third group on a boat dive, with or without sharks. Marcos and his crew are exceptionally warm and friendly, and obviously very qualified and experienced. With their great staff and wide range of services, Dive Balam has a 5/5 rating on Trip Advisor and excellent reviews across the web. They not only do their job well, they also take great care of their customers in providing safe, quality diving training, service, and trips. It’s obviously something that’s always nice on a dive vacation, and takes on a much greater importance when you’re going to be diving with bull sharks.

The dive center is located within the resort itself, in the middle of a large courtyard just a few dozen yards from the resort swimming pool and beautiful white-sand beach the area is so famous for. Those going out on boat dives walk down to the beach to board one of Dive Balam’s dive boats. For trips to the Yucitan’s famous cenotes, they arrange and provide ground transportation to their divers.

In addition to being a master instructor, Marcos is also a shark diving expert who has studied bull sharks firsthand for well over a decade. He’s spent hundreds – perhaps thousands – of hours underwater with them, observing and learning their behavior and getting to know the personalities of each one. The bull sharks he dives with are all unique individuals with names, distinct markings, and personalities as diverse as humans, and Marcos knows each one. It’s with this knowledge and understanding that he not only dives with them on an almost daily basis, but also hand feeds them. Experienced divers can come along and observe this on Dive Balam’s daily shark diving trips which run from September or October through February each year, when the bull sharks are usually in town. (Experts believe that these mothers-to-be are in search of a nursery, so when the time to give birth arrives they swim to nearby fresh waters, only to return to Playa del Carmen with their young). Our timing on this trip in January was towards the end of that season, but right on cue, the sharks arrived within minutes of us arriving at each site and provided us with a fascinating experience in six dives over three days.

A brief introduction to bull sharks

Bull sharks are truly fascinating animals. The bull shark is diadromous, meaning they can swim between saltwater and freshwater with ease – a very uncommon characteristic among sea animals. It’s a process they have physiologically adapted to, and some scientists have speculated that it was an adaptation which took place during the ice age, when sharks were trapped in fresh water environments. To survive in fresh water, bull sharks possess several organs with which to maintain appropriate salt and water balance in their circulatory systems and body. While it’s possible for the bull shark to live in fresh water for its entire life, it has been observed that this does not happen for certain reasons, mostly due to reproduction. They can travel far up rivers (one was even caught last year in Ohio), and have been known to travel as far up the Mississippi River as Illinois.

Bull sharks are rightfully known for their aggressive nature and predilection for warm shallow water, which is one reason people are more commonly injured by them. They are likely responsible for the majority of near-shore shark inflicted injuries, including many which are attributed to other species. While they can be found to a depth of almost 500 feet, they do not usually swim deeper than 100 feet (30 meters). Our dives off Playa Del Carmen were at a depth of 60-75 feet, which is home for them most of the time.

Bull sharks regularly feast on other sharks, fish, turtles, sting rays, mollusks, and even birds. Like most sharks, they aren’t picky about their diet so they will generally eat what is readily available. Despite recurring stories of people being attacked by bull sharks (and other species of sharks), humans aren’t on their list of usual prey, and virtually all “attacks” are the result of misidentification or of the sharks being territorial.

As an apex predator, sharks don’t have too much to worry about underwater. While tiger sharks and great white sharks may attack them, by far their biggest threat is humans. Even in the Riviera Maya, where they are sometimes targeted by fishermen, only to be killed for a meal or two – and sometime just for sport.

One of Playa Del Carmen’s biggest threats are Fishermen who kill pregnant and baby bull sharks year after year. In Playa del Carmen, some conservation efforts have focused on stopping one man from nearby Puerto Morelos. Critics say his fishing alone has had a noticeable effect on the local bull shark population. Photos in which he poses proudly next to his day’s catch have spread over the Internet, enraging many. The actions of Luis Lombardo and Saving Our Sharks organization ending one fisherman’s quest to kill the sharks by taking action to have his permit revoked – after killing 25 females in one night.

Unfortunately for bull sharks, they are classified by the International Union for Conservation of Nature (IUCN) as a low-risk, near threatened species and not legally protected. Its meat in Mexico sells for little (two pounds cost less than $3). Many are caught just for sport; their carcasses buried or tossed into landfills with the “reward” for fisherman being the adventure of catching one.

During our dives, we witnessed up to 11 bull sharks at any one time. It’s very easy to see how quickly these beautiful animals could be killed and leave us with nothing to see again.


Pre-dive briefing

As when any group of divers arrives, Marcos gave us a very comprehensive pre-dive briefing at Dive Balam the morning of our first dive. The briefing thoroughly covered our dive plan, which quickly showed why this is considered an advanced dive, as well as important information on the behavior of the bull sharks we would be diving with. Below is a brief excerpt where Marcos reviews our dive procedures and a reminder to “always listen to your instructor” (something that is often followed more closely by newer divers vs. those more experienced).

While the visibility was excellent (100 feet +) and surface conditions near perfect, the area just offshore where we would be diving does have a strong current. When observing Marcos feeding the sharks, divers gather together and lay nearly flat on the seabed, shoulder-to-shoulder, which obviously requires divers to be properly weighted. This was one time when many of the divers in our group thought they had their buoyancy perfectly calculated, only to be asking for more weights after the first dive. Admittedly, I was one of those divers who was underweighted and added a few more pounds after my first dive.

Wearing a full 3mil suit (without a hood), I would normally take about 6-8 pounds of lead with me. After our first dive I bumped that up to 12, then added another 4. A few other divers in our group had a similar experience, adding weight after the first few dives. (Remember the old adage – “listen to your instructor”!). While 16 pounds of weight would seem very excessive for most dives, the current here was not only strong but curiously “gusty”, and being able to stay comfortably out on the bottom made the difference between being able to relax and watch the action vs. struggling to hold position.

Each dive would take place in about 60-75 feet of water, providing roughly 30 minutes of dive time per dive. At the end of the dive, the accompanying dive masters would give the signal to group together and we would all surface as one unit, following a line up to a surface marker buoy launched by our leader. This is important, as the current can quickly separate individual divers here. The live boat at the surface was very attentive and ready to pick us up wherever we surfaced – standard here, but a real luxury for those of us accustomed to doing a lot of shore diving.

Twenty minutes later, we had a plan in place and were ready to board the boat. In true resort diving style fashion, the crew at Dive Balam already had our weights, tanks, regs, and B.C.’s loaded on the boat for us. We walked down to the beach and climbed aboard, ready for an adventure (and excited for some great photo opportunities).

Scott & Marcos planning the dive. Both are wearing chain mail suits for additional protection.

Scott & Marcos planning the dive. Both are wearing chain mail suits for additional protection.

Swimming with the bulls

After a twenty minute boat ride, we were at the dive site, eagerly waiting to descend. Marcos and Scott Cassell were fully geared up in their chain mail suits and helmets; the rest of us in our regular scuba gear. After everyone was fully geared up, we all entered the water quickly so we could stay as a group. After a quick surface check, we descended down – clearly seeing every detail of the bottom, 70 feet below through the clear water.

Upon our initial descent we were able to see two bull sharks circling on the bottom below us. Staying together as a group, as instructed, we gathered together on the bottom, shoulder t0 shoulder, laying or kneeling down. Marcos and Scott set up in a standing position about 40 feet away with their bait buckets, ready to hand feed the sharks, and our guide checked each diver to make sure we were all ready to go. It wasn’t long before the sharks arrived.

Diving in a current here was part of the plan, and a necessary one. Since Marcos and Scott were actively attracting and feeding the sharks, having a current carry the scent of the bait was key to bringing in the bulls. Without a current, the scent does not carry through the water and makes it harder to attract them. Once they’re there, the sharks tend to follow the scent, and it’s makes it more predictable as to where they will be swimming at any point in time. Without a current, the baited water forms a sort of cloudy area around all the divers, making them less predictable. Here’s a clip from one of our dives and a few of our early shark encounters (not the current by the direction of the diver’s air bubbles).

At first, two large bull sharks arrived, one with a shark tag hanging off her dorsal fin. While these dominating animals are known for being aggressive, it took them time to “warm up” and get near Marcos and Scott, even with them generously offering large pieces of cut up bonita to the sharks. It reminded me of a stray dog being offered food from a stranger, approaching cautiously and tentatively. It took about 10 minutes for one of them to finally swim up to Marcos and grab the offering from him, rapidly turning away and speeding off with the catch.

In time, others joined in and as many as 11 sharks joined the party. There was a noticeable increase in speed and activity as more sharks arrived, and they much more readily took the bait from Scott and Marcos. When not going for the food, the sharks regularly made nearby passes to those of us observing, getting as close as 6 feet away before gently veering off and away, only to circle back again. They also regularly swam around behind us, closely monitored by our dive leader who strategically positioned himself during every dive so they would keep a safe distance from our backsides. These ‘drive-by’ encounters provided us with great photo opportunities and the reward of being literally face-to-face with these magnificent animals of the sea.


With a current raging, air running low, and more and more sharks arriving for free handouts, it was time to end the dive. Following Marcos’ pre-dive plan, we gathered together, our leader launched a SMB, and we ascended to the surface and boarded the dive boat. After lunch and surface interval, we dove in for a second dive encounter each day in the same area.

Over the course of the next few days we logged 5 more dives, each proving as rewarding as the first, and each following the same basic dive profile. Thanks to Marcos’ knowledge of the sharks and area, we encountered sharks on every dive and were treated to near-perfect dive conditions (and a seemingly reduced current with each subsequent dive). Each dive became more comfortable than the last and each experience brought a closer level of connection with the sharks.


Lion fish sushi

After the first two days of diving, it was time to participate and observe in one of the most important missions of this trip – to see if bull sharks would eat the invasive lion fish. As written in our earlier story, lion fish are native to Indonesia where there are preyed upon by sharks; as a relative newcomer here in Mexico, sharks do not yet recognize them as a food source, and so far have not been observed eating them. Doing so would mean the lion fish populations might be able to be reduced by a natural predator. If bull sharks don’t recognize them yet as a food source but developed a taste for them, could they be taught and conditioned to eat them?

Replacing the cut bonita with lion fish, on the third and final day of our mission the sharks were offered lion fish to the sharks in the same manner they had been fed earlier. The water conditions were identical, the sharks arrived as they typically had, and the divers positioned themselves the same. Would they go for the free offering?

Unfortunately, they did not. Over a period of 30 minutes, only a few lion fish were grabbed by the sharks, and after a taste were actually released from the shark’s mouth. One shark made several attempts and ultimately consumed one lion fish, but not nearly as eagerly as eating the bonita. It seems as though they aren’t keen of lion fish after all, even as a free handout.

Scott Cassell has speculated that the lion fish may have been conditioned since September to enjoy only the bonita when handed out by divers; this is what they are typically fed by Marcos and his crew. Next season further tests and observations will be carried out under similar conditions to see if they will eat lion fish when fed them exclusively and earlier in the season.




While bull sharks are known to be aggressive towards humans, due to their knowledge of sharks and experience diving, Marcos and the team at Dive Balam have a perfect safety record in diving with them. Every step of the way, the dives were carefully planned and executed.

“Marcos Mier started the program, and I won’t say that he’s tamed them, but he’s conditioned them to be around people in a non-aggressive state.” said Scott Cassell. “You don’t want to push bull sharks, but these are calm animals.”

Interestingly, on several of our dives, we were joined mid-way by other small groups of divers who took up position behind us to watch the feeding. While some locals object to hand-feeding the sharks, they, and other local dive shops, recognize Marcos as the expert in the area and will bring their guests over to watch him feed the sharks. An agreement in place between the shops means Dive Balam divers get the front row seat, however.

Value of bull sharks

In addition to investigating whether or not bull sharks will eat lion fish, the mission to dive with bull sharks in Mexico was also important to educate people about the value of bull sharks to the local economy. Divers who enjoy observing bull sharks swimming and being fed are a valuable resource to the town of Playa Del Carmen, the travel and dive industries, and a wide range of other businesses. With a lifespan of 10-12 years, one shark has enormous income potential – if kept alive.

Marcos Mier, Scott Cassell and other concerned members of the Playa Del Carmen community understand this and are working very hard to educate both locals and travelers about the importance of bull sharks to their local economy. One dive trip with bull sharks can cost anywhere between $70 and $160, and one live shark alone can yield up to $220,000 per season (literally one thousand times more than one dead shark). Multiply that times 25 (the record number of sharks recently counted in that area), then add hotel, transportation and food costs, and you get a source of income for many businesses that help hundreds of local families keep afloat. In every measurable way, the bull sharks are worth far more alive than dead.

“What’s not really being done is generating reasons for people to care about sharks. To do this, you need to educate people and give them information about the sharks.” Scott Cassell explains. “This is where La Riviera Maya can lead the world and make a lot of money doing it. Right off the beaches of La Riviera Maya are beautiful bull sharks… one of the last populations of this size on earth. This species is being hit hard by shark fishermen and are nearly extinct from soulless over-fishing.”

“Hundreds of thousands of people travel each year just to see sharks. The Bahamian Tourism Board determined that each Shark off their coast is worth over one million dollars each to the economy… and the Palau, Australia determined their sharks are worth two million dollars alive (each).”

Indeed. A report released April 17, 2012 found that shark diving driven by the tourism sector earned the Fijian economy more than $42 million in 2010, of which $4 million went to local communities in the form of salaries and local levies.

Saving sharks – just by going diving

Even without donating time and money to shark conservation causes, divers can literally save sharks just by going diving, either here at Playa Del Carmen or in other areas where sharks can be found. By visiting areas where sharks are abundant and supporting dive shops and other businesses, combined with divers educating others about the excitement and reward of seeing sharks underwater, divers can help protect these beautiful animals and help change the attitude towards them. The concept of ‘save the whale’ was as foreign in the early 1970′s as ‘save the shark’ now is, and divers can help change this.

Divers also have a unique connection with both the underwater world and non-divers, who may have little factual knowledge of sharks and other life underwater. Sharing positive experiences of interactions underwater can be a powerful way to change the fear of the ocean’s creatures that many people have, and sharks in particular. There’s no doubt that at some point in time, you’ve been asked, “have you ever seen a shark while scuba diving”? Sharing photos, stories, and positive information about your encounters can have a powerful effect and change the mindset that has, in part, resulted in over a billion sharks being killed over the last decade.

When you go

Playa Del Carmen is a beautiful area and has a wide range of accommodations for everyone. There’s plenty to do here for divers and non-divers alike, and with easy air travel and a host of all-inclusive resorts, it’s a great location for the entire family.

Diving with bull sharks is seasonal. They normally arrive between September and October and depart again in February, though there are plenty of other diving options the rest of the year at Playa Del Carmen.

Several dive shops dive with the bull sharks, however if you’re interested in a front-row seat, Marcos and Dive Balam is highly recommended. For more information on Dive Balam, visit their website here.

Dive safe.

Words & Photos by Chris Constantine, California Diver Magazine

Additional Links/Resources:

Dive Balam, Playa Del Carmen
Luminox / Luminox Mexico
Royal Haciendas Resort
SOS – Saving Our Sharks
Strange Media
Tuna Cinema
The Undersea Voyage Project
Wikipedia: Bull shark